Kernel 6.14 - minimum CPU frequency changed?

Framework Laptop 13 Linux
1

Hi,

I’m just wondering if anyone know what change between kernel 6.13 and 6.14 that could have resulted in my cpu’s minimum frequency being 1100 mhz instead of 400mhz like before?

I’m inquiring because it’s resulting in higher idle temps causing the fan to kick in when previously it would never kick in.

Thanks in advance for any information on this.

Dominique

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2

Ok I figured it out.

$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq
1100000
$ cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_min_freq
400000

To temporarily change it back to 400mhz
$ echo 400000 | sudo tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_min_freq

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3

Uh I was wondering this today too, just happened to notice it today.

wonder what was the factor for this change, or is this just a misshap

4

Likely this? https://gitlab.freedesktop.org/upower/power-profiles-daemon/-/merge_requests/198

Power saver drops CPU clocks to 400MHz for me.

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5

Thanks for the extra info.

Using
tuned-adm profile powersave

Doesn’t seem to change it on my fedora 42 beta install.

Could it have to do with amd_pstate_epp vs amd_pstate passive?

Looking at fedora kernel git log at some point last summer amd_pstate default mode was changed to 3

diff --git a/kernel-x86_64-fedora.config b/kernel-x86_64-fedora.config
index a0b2e5b2e..c7544c398 100644
--- a/kernel-x86_64-fedora.config
+++ b/kernel-x86_64-fedora.config
@@ -347,19 +347,6 @@ CONFIG_ARCH_RANDOM=y
 # CONFIG_ARCH_SA1100 is not set
 # CONFIG_ARCH_SPARX5 is not set
 # CONFIG_ARCNET is not set
-CONFIG_ARM64_AMU_EXTN=y
-CONFIG_ARM64_E0PD=y
-CONFIG_ARM64_EPAN=y
...skipping...
+CONFIG_X86_AMD_PSTATE_DEFAULT_MODE=3
 CONFIG_X86_AMD_PSTATE_UT=m
 CONFIG_X86_AMD_PSTATE=y
 CONFIG_X86_ANDROID_TABLETS=m
6

That change seems pretty strange to me. Wouldn’t you want to prioritize absolute lowest power use over efficiency for your lowest clock state which presumably you are at when your system has little or no work to do, or am I missing something?

7

ohh i have this too? :thinking:

8

Not if it consumes more power overall to spin it back up to a usable speed, for instance.

I’m gonna trust the revised defaults from AMD on this one

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